updated 03:09 pm EDT, Tue June 12, 2012

Net giants comprise all of the top five trackers

Google and Facebook are watching Internet users' movements across the web more than any other companies, according to a new analysis out from the makers of the Ghostery browser-privacy plug-in. The study used traffic data from more than a million users. It found that all of the top five trackers on the Internet were either Google- or Facebook-affiliated, with Twitter also making the top ten.

The Evidon Global Tracker Report is biennially produced by Evidon, whose Ghostery browser plug-in monitors and blocks third-party Internet trackers. The latest report monitored tracking cookies for more than 1.6 million users.

Google Analytics was the most common tracker, followed by Google Adsense, Facebook Social Plugins, Google+1, Facebook Connect, and the Twitter Button. Among advertising networks that retain information about user browsing in order to later serve ads, Google Adsense, DoubleClick, and Google Adwords Conversion were among the top five most common trackers detected.

The study found that the average website has 4.7 trackers of some form on it. Also, every tracker on a site was found to add to the time it takes for a page to load. The average latency was roughly half a second per tracker, but some trackers added more than three seconds to loading time.

The study is not without its potential flaws. The data was collected from Evidon's Ghostery extension users, which represent a subset of Internet users likely more concerned about privacy and tracking than the general populace. Additionally, Evidon produces a program that lets users find out what ads are tracking them, which introduces an aspect of impartiality to the study. Nonetheless, the results demonstrate the pervasiveness of user tracking across the Internet, which is an issue for which Facebook and Google, among other companies, have previously come under fire.